Dimethylaminopivalophenone[1][2] is an opioidanalgesic with a potency ½ that of morphine.[citation needed] It was initially discovered by Russian scientists in 1954 and subsequently rediscovered in the US in 1969.[3] Its LD50 in mice is 83 mg/kg.[4] It has never been marketed commercially.[citation needed]
^Atwal MS, Bauer L, Dixit SN, Gearien JE, Megahy M, Morris R, Pokorny C (November 1969). "Analgetics. II. Relationship between structure and activity of some beta-amino ketones". Journal of Medicinal Chemistry. 12 (6): 994–7. doi:10.1021/jm00306a006. PMID5351480.